H. Saijo et al., DIRECT OBSERVATION OF THIACARBOCYANINE J-AGGREGATES ADSORBED ON AGBR EMULSION CRYSTALS, USING HIGH-RESOLUTION SCANNING ELECTRON-MICROSCOPY, Journal of imaging science and technology, 38(5), 1994, pp. 455-459
-sulfapropyl-5,5'-dichloro-9-ethylthiacarbocyanine dye J-aggregates ad
sorbed on AgBr microcrystals grown in gelatin were imaged in a high-re
solution scanning electron microscope when the incident beam energy wa
s as low as 700 eV. At this voltage, the resolution of the microscope
was 3 nm. High-resolution observation could be made at room temperatur
e without irradiation damage. Specimen cooling by liquid N-2 made the
image flat through accumulation of electronic charges on the specimen
surface caused by low electron conductivity at low temperature. The J-
aggregates aligned linearly along [210] directions on the (100) surfac
e of AgBr as if they were one rod-like aggregate. The rod-like aggrega
tes were frequently found to form clusters aligned parallel to each ot
her. The aggregates sometimes built up a terrace with many rodlike agg
regates to almost cover the surface. The edge of the terrace was clear
, and no aggregates seemed to adsorb on the other side of the step. Th
ese superstructures of J-agaegates caused heterogeneous distribution o
f adsorption on the crystal. surface. Cathodoluminescence observation
confirmed these results.